Apparatus for testing and sorting thin rubber articles



Aug. 25, 1953 J. R. GAMMETER' APPARATUS FOR TESTING AND SORTING THIN RUBBER ARTICLES Filed June 10., 1949 4 Sheets-Sheet 1 INVENTOR.

JOHN R, emmsrsa ATTORNEY Aug. 25, 1953 J. R. GAMMETER APPARATUS FOR TESTING AND SORTING THIN RUBBER ARTICLES 4 Sheets-Sheet s Fil ed Jun- 10, 1949 INVENTOR. JOHN R. GAMMETER Aug. 25, ,195 3' 'J." R. GAMMETER 2,649,960

' APPARATUS FOR TESTING AND SORTING THIN RUBBER ARTICLES- Fiied June 10, 1949 r v '4 Sheets-Sheet 4 IN VEN TOR.

JOHN R. GAMMETER ATTORNEY Patented Aug. 25, 1953 APPARATUS FOR TESTING AND SORTING THIN RUBBER ARTICLES John R. Gammeter, Akron, Ohio Application June 10, 1949, Serial No. 98,332

Claims.

This invention relates to apparatus for testin and sorting thin articles, and particularly thin hollow rubber articles.

Gammeter Patent No. 2,221,323 disclosed apparatus for testing thin rubber goods for defects, by passing the goods received on metal forms into rolling engagement with the underside of a flexible element of metallic mesh material. While this prior structure was generally satisfactory, the effective area of contact between the article and the element was somewhat reduced because conformity of the same about the article was dependent upon non-uniform gravitationally applied forces, particularly around the freely projecting end of the article on the form.

The ,prior Gammeter patent, No. 2,371,818, shows article-discharging apparatus which might be utilized in conjunction with such testing equipment for removing the articles from the metal forms, but which was limited to use for removing only the good articles from the forms, additional equipment having been necessary for removing the defective goods before reachin said article discharging apparatus. One type of equipment for this purpose utilized blasts of air projected through holes in the ends of the forms, to blow the articles therefrom, but the air holes minimized the efliciency of the testing apparatus to a certain extent because of the absence of metal for passage of electrical current when the defects coincided with the air holes.

One object of the present invention is to provide improved, highly eflicient means for electrically testing thin rubber goods for defects, wherein is assured maximum complete coverage of the desired area of the article to be tested including, for example, rounded end portions of elongated hollow rubber articles.

Another object of the invention is to provide improved mechanism for sorting outdefective articles as manifested by said testing means, by which is eliminated the use of objectionable air holes in the article-carrying forms which might otherwise allow some defective articles to pass as good ones.

Another object of the invention is to provide testing and sorting apparatus of the character described which is substantially fool-proof and free of the restrictions usually incident to the human element.

Other objects of the invention will be manifest from the following brief description and the accompanying drawings.

Of the accompanying drawings:

Figure 1 is a top plan view, partly broken away, illustrating improved apparatus for testing and sorting thin rubber articles.

Figure 2 is an enlarged vertical cross-section through electrical testing unit embodying features of the invention, the same being taken substantially on the line 22 of Figure 1.

Figure 3 is a cross-section taken substantially on the line 3-3 of Figure 3, showing a form passing through the testing unit.

Figure 4 is a view similar to Figure 3, but illustrating the condition in which no form is'passing through the unit.

Figure 5 is a cross-section of an improved article sorting unit embodying features of the invention, in operative position for removing articles from forms, the same being taken substantially on the line 5-5 of Figure 1.

Figure 6 is rear elevation, partly broken away, of the sorting unit as viewed from the left of Figure 5.

Figure 7 is a view similar to Figure 6, but showing the unit in inoperative position with respect to the forms.

Referring to the drawings, the numeral Ill, H3 indicate a plurality of metal forms rotatably supported on mountings H, H peripherally spaced on an annular conveyor or plate I2. This conveyor I2 is mounted to rotate about a fixed circular table I3, in clockwise direction as viewed in Figure 1, to convey the forms through an electrical testing unit T for manifesting defective articles on the forms, and also for conveying the forms past an article-sorting unit S which automatically discharges the defective articles from the forms, as manifested by the testing unit. Suitable mechanism for rotating the conveyor I2 about a vertical axis at the center of the table I3 is illustrated in said prior Patent No. 2,221,323. The forms as shown are of suitable shape to receive thereon in distended, unwrinkled condition, thin hollow rubber articles A, such as prophylactics, finger cots, or the like which are open at one end and rounded at the other. That is, the forms are electro-conductive while the articles thereon are of dielectric material, which characteristics are utilized in the present process for testing the articles.

In order to facilitate application of the articles to be tested onto the forms Ill, at a point to the right of the tester T as viewed in Figure 1, the forms extend freely radially inwardly of the conveyor l2 at an upwardly inclined angle. For rotating the forms as they move through the testing unit T, a suitable length of toothed rack i4 secured to the fixed table it is engageable by pinions i5 fixed on the ends of the forms adjacent the mountings thereof.

For electrically testing the articles, the rotating forms are thus moved in succession through testing unit T. Each form, while rotated by engagement of'its pinion [5 with rack t t, is moved in an arcuate path into yielding engagement with a flat, resilient pad 55 presented upwardly on a hard backing plate H, which is mounted on a support it. This support includes a: sleeve l9 vertically slidably adjustable on an upright rod-2P3 fixed on table it, and a head 22 swivelly connected to said sleeve, said backing plate being secured to said head. The swivel connection for said head may include a ball joint 2% having a clamping nut which is rotatable to clamp the head with said pad thereon in various angularly adjusted positions with respect to, the horizontal, and in particular to adjust the plane of the upper surface of the pad; It so that whena form is rolled over the pad the latter will conform, to. approximately one quarter of the surface area of" an article A on the form. Verticaladjustment of the sleeve on rod 28v is accomplished through a set screw The pad it may be of soft resilient material such as foam rubber or like spongy elastic material, and the exposed rubber surface portion thereof may be covered with a thin element 26 of flexible electro-condnctive material, such as fine wire mesh fabricof the type used for ladies handbags. Thus, the element 26 is limply flexible or flaccid and, therefore, deeply depressible with the material; of'thepad to conform to a substantial proportion of the. surface area of an article A on said: form. In order that the resiliency of pad it? will not be materially detracted from, the trailing edgeof element. may be secured to a corresponding edge of. the-backing plate H, and the leading end of element 25 weighted at 26a for yielding-lymai-ntaining the element intaut condition: over the topof pad iii.

The electro-conductivc element and each form lilare suitably connected in. any electrical circuit (not: shown) providing a source ofhigh potential current (approximately 1260 v.). Completion. of. the.circuitathrough. the element and a form passing over the same isznormally prevented by presence of a rubber article A on. the form. A I

suitable circuitfor this purpose isshown and describedv in said: Patent No. 2,221,323,. wherein the electricalpotential. is. sufficient to leap an. air ga p'corresponding to. the wall thickness of article A butnormally insufficient to pierce the goods. That is, when the articlescontain thin spots, or are predetermina-t'ely under gauge, or have pin holes in thesame, current will jump. the gap provided betweenfo'rm it andele'ment fifithrcugh the wall of the article (see Figure 3,) and will flow through the high-tension circuit. This closing of the electrical circuitzmay, be utilized to manifest the presence of articleswhich are defective for the reasons stated; in a manner to be described later. Element 261s: insulated from the table it by the dielectric nature of the rubber pad id.

The elementv 2 6 may be supplemented by a similar element 2 of. flexible wire mesh suspended in sagging relation whereby the element adapted to drape: over and conform to the upper portions of a form, passing. over the pad 55, the element 2?: being connected in said high potential circuit, in, parallelism with element 26 and being normally insulated. from, the form by the rubber article thereon as described above and otherwise being operable substantially in the manner set forth in Patent No. 2,221,323. Element 2'! may have dependent therefrom, a strip of similar flexible wire mesh fabric, constituting an apron 23a adapted to conform closely to the rounded inner ends of the articles on the forms. Because the elements 26 and 2? are in parallelism in thecircuit they may-"contact each-other without disturbing the effectiveness .of the circuit.

The presence of defective goods on a form It is electrically manifested in the sorting unit S, automatically tostrip the defective article from the form and eject it into a funnel 28, mounted on table [3, to drop into a container (not shown).

The sorting unit S includes an endless 'v-belt 29, which may be of fabric-reinforced rubber, extendedbe'tween two pulleys 3t and 3! rotatably mountedon a vertically shiftable bracket 32, the shaft or spindle 33 of one pulley 3i being rotatable therewith and having an extension. 34- to which is attached a flexible cable 35 from. a power-driven device (not shown) for rotating; the pulley and thereby operating the belt to move. the straight upper reach'thereof in a direction in,- wardlyof the conveyor [2,

Bracket 32 is vertically shiftably mounted. for moving said belt toward and from the path of the lower surface portions of the forms carried by conveyor l2. Accordingly, the brachetis vertically adjustably secured on the free end. of an arm 33 which is pivoted at its. opposite end to, a fixed upright on a base 3 1 suitably secured to table it, the arm 36 being yieldingly urged toward a raised position as by means of a compression spring 38 arrangedbetween a pivoted lug. 39 adjacent the free end. of arm 36 and a fixed lug mounted on said base. An elongated bolt ll may extend from the pivoted lug 3S downwardly through spring 38 and an aperture infixed lug Gil, the lower end of the bolt having nut diedjustably threaded. thereon for limiting upward movement of bracket arm 3% as urged by the spring.

The arm 36 and component parts are adapted to be normally releasablyheld in the lowered position shown in Figure 7, to be away from the path of the forms ill, by a downwardly extending finger lt having an edge 4'4 thereof engaging a shouldered or notched portion 45 in a trip-lever i6 extending in horizontal directionfroma shaft i? pivoted between spaced lugs 43 and 49; the arrangement being such that spring 38 tendsto urge the finger 13 into firm stop engagement with the notched portion of lever 46. Extending horizontally outwardly of-shaft 11. inthe opposite direction from. lever 46 is an arm 511; which is apertured slidingly to receive a threaded pin 52 extending from the lower end of any armature. 53 of an electro-magnetic coil 5 mounted on a bracket 55 on. base 3:71 The coil 541is connected to the above described electrical; circuit to be momentarily energized upon passage of current between any form. {0 having a defective article thereon, and either-one or. both; of the elements 26 and 2?. Energization of the coil, is effective to withdraw the coil armature 53 upwardly and thereby engage ahead- 56 onpin 52- with the underside of arm: 51, which pivots trip lever 43 downwardly, thereby disengaging finger 1.35 from the lever 46 and allowing spring 38 to urge arm 36 upwardly until nuts 42 engage lug 40, as shown in Figure 6; In this upposition of arm 36 the upper reach of belt 29- is positioned in the arcuate path of the lower portions of forms t0 and engages the articles lengthwise to strip the same from the forms. When the articles of the type shown are provided with integral reinforcing rings 51 the belt may be driven at a desired linear speed with relation to the speed of the conveyor 12 to engage the rings 51 and roll the articles 'upon themselves toward the 'free inner ends of the forms and finally eject the rolled article into said chute 28. In order to assure efficient removal of the articles from the forms, the upper reach of belt 29 preferably is arranged to engage the articles at a slight angle to the longitudinal axis of the forms.

After a defective article A has been ejected from its form it it is desirable to reset the sorting unit with the belt 29 in lowered position, so that a next succeeding form having a perfect article thereon may be carried by conveyor [2 to a station (not shown) at which the perfect articles are removed from the forms in any suitable manner. To this end, any form l upon passing over the belt 29 in raised position thereof, moves into contact of a base portionthereof with aroller 53 on the upper end of a rod 59 vertically adjustably secured on the pulley-support ing plate iii] of pivoted arm 36 (see Figure and thereby urges said arm 36 downwardly against the action of spring 38 until finger 43 reengages trip lever Gt, to lock the arm 36 and associated parts in the lowered position shown in Figure 7. An adjustable counter-weight 62 on the free end of arm 5! assures that trip lever 46 will be held in frictional engagement with the finger 43 at all times; As coil 54 is only momentarily operated by the testing apparatus, for each defective article, the armature 53 does not affect reengagement of the trip mechanism as described.

In operation of the apparatus described for continuously testing and sorting thin rubber articles A, and operator stationed at the right of testing unit T (as viewed in Figure 1) applies an article to be tested to each form it on annular conveyor I2 as it is continuously rotated about table [3, the articles fitting on the forms in smooth unwrinkled condition. The forms pass in succession between the testing elements A 26 and 21, which are so proportioned in size with respect to the spacing of the forms that no more than one form at a time can be in contact with the elements. Each form in moving into contact with element 26 of pad l6 yieldingly depresses the pad to conform the element about the lower half of the article on the form, the form at the same time being rotated against the surface of the element in direction opposed to the direction of arcuate travel of the form and at a greater linear speed than the conveyor,

thereby assuring maximum contact between the element and the outer surface of the article, including the closed free end of the article. Frictional engagement of the draped upper element 27 with the upper surface portions of the article on its moving form adds to the efficiency of the device.

Complete coverage of an article being tested is assured by the fact that in addition to dragging engagement thereof against the upper element 26, there is a rolling yielding engagement of the same against the element 21 for approximately one and one-half revolutions of the form.

If rubber articles on the forms [0 are perfect as to gauge and quality they will provide requisite insulation between the electro-conduotive elements 26 and 21 and the metal forms moving between said elements. Should a form passing between the elements contain an ar- 6. ticle which is under gauge, in whole or in part, or which has even a tiny pin-hole in it, a current of high potential electricity will fiow between the element 26 and/or '21 and the respective form, momentarily to energize the electro-magnetic coil 54 of sorting unit S.

Momentary energization of electro-magnet 54 of unit S instantaneously operates trip-lever :16 to release finger 43, allowing spring 38 to urge arm 35 upwardly and present the upper reach of bolt 29 in the path of the form containing the defective article as it leaves the testing unit. Accordingly, the upper reach of the continuously moving belt will engage the article in lengthwise direction thereof and strip it from the form, the force applied by the belt being effective to project the stripped article directly into the defective goods funnel 28.

Immediately after the thus bared form moves past the belt 29 the roller 58, carried by the beltsupporting arm 36, is engaged by said bare form to urge arm 35 downwardly against the action of spring 33, until the finger 43 is in locked engagement with the trip lever 46 for holding the belt out of the path of movement of the forms. It will be readily seen that the apparatus is adapted for effectively testing and sorting articles on adjacent forms in quick succession.

The apparatus of the present invention is not only highly efiicient in operation, but is substan tially fool-proof in the detection of defective articles of the character described.

Modifications of the invention may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

1. Apparatus for testing thin rubber-like articles of dielectric material for defects, comprising an elongated electro-conductive form of generally cylindrical cross-sectional shape and having an outer end portion on which form the article may be received in distended condition, relatively fixed supporting means including a relatively rigid backing member, a resiliently depressible pad of soft spongy elastic material mounted on said backing member and presenting a face of broad lateral area freely outwardly, the outer surface portion of said face constituting a relatively thin layer of flaccid electro-conductive material, the pad being relatively thick and the layer being highly flexible so that the same is conformable to substantial depth with the spongy material of the pad under edgewise pressure of said form to embrace and contact a substantial radial depth of the form and contact said end portion, conveyor means for rolling said form across said surface portion of said pad and appiying said edgewise pressure of the form against the pad and thereby yieldingly to depress said pad and conform said electro-conductive layer to a substantial proportion of the surface area. of an article on the form, means for maintaining electrical potential between said form and electro-conductive layer sufficient to leap an air gap through the wall of the article, or to pierce an article of less than predeterminately normal thickness, and responsive means for manifesting passage of electrical current between said form and said electro-conductive layer.

2. Apparatus for testing articles of dielectric material for defects, comprising an electro-conductive form on which the article may be received, relatively fixed supporting means, including a relatively rigid backing member,- a resiliently depressible pad of spongy elastic material; mounted on. said backing-member and presenti'ng. a face thereof; of broad lateral area freely outwardly", atzleast: theouter surface portion of; sai'cl' face beingrof limply flexible electroconductive material, means" for relatively, con-- veying said form across: saidv surface portion of said pad; yieldingly to depress the padxto: a substantial depth and'thereby'conform said; flexible surface portion thereof to a substantial area of the surface of an article on the form, and means for maintaining electrical potential between said form andv said electro-conductive surface portion sufficient to leap ana-ir gap through the wall of the article or to pierce an article of less than predeterminateiynormal thickness, and respon sive meansformanifesting passage of electrical current between saidform. and electro-conductive surface portion, said surface portion comprising an element of, flexible metallic mesh fabric-mounted. against said pad.

3. Apparatus for testing articles of dielectric material for defects, comprisingan electro-conductive form on which the article may be receivedrelatively fixed supporting means including a relatively rigid backing member, a resiliently depressiblepact of spongy elastic material mounted on said backing-v member and presenting a face thereof ofbroacl lateral area freely outwardly, at least the outer surface portion of said. face beingof limplyflexible electroconductive material, means for relatively conveying said form across saicl surface. portion of said. pad yielding-1y todepress the padto a substantial depth and, thereby conform said flexible surface portion thereof to a substantial areaof the surface of an article on the form, and means fer. maintaining-electrical.potential between said formand said lelectrorconductive surface portion sufficient to leap-an air. gap through the. wall of the article-or to pierce an article of less. than predetermi-natelynormal. thickness, and responsire means for. manifesting passage of electrical current between said form andelectro-conduce tive surface portion,.said apparatus including a series of said.- forms, said surface portion of-said pad being upwardly presented, a member of, flexib-le metallic. mesh. fabric being mounted in sagging condition over saidpad for conforming to the upper surface portions of articles on the forms, said form-conveying means including mechanism for rotating said. forms in succession between said member and'said-surface portion, said-member beingin electrical connection with said electrical potentialmeans to the-forms.

4". Apparatus .as set-forth in claim 1, saidbacking member being angularly and-vertically adjnstabl-y mounted with respect to the path of rolling movement of said form by said conveyor means.

5. Apparatus asset forth in claim 1,v wherein said form is rotated against said electro-conductive layer in direction opposed to the forward travel of the form and at a greater linear speed than said forward travel of theform.

JOHN R.

References Cited irr the file of. this patent UNITED STATES PATENTS Number Name Date 1,952,582 Cory Mar. 27, 1934 2,155,977: Miller: Apr. 25 1939 2,221,323 Gammeter Nov. 12-, 1940 2,297,663 Strassman Sept. 29,1942 2,299,230 Gammeter Oct. 20', 1942 2,353,256 M-aywald July 11 1944 2,371,813 Gammeter Mar. 20, I945 2,480,142 Lager Aug. 30, I949 

